Other factors may also cause these sleeping problems, such as emotional concerns or medical conditions unrelated to cancer.

Relieving side effects is an important part of cancer care and treatment. Treatment to manage side effects is called symptom management, palliative care, or supportive care. Talk with your health care team about managing or coping with sleeping problems.

Hypersomnia

People with hypersomnia feel very sleepy during the day or want to sleep for longer than normal at night. Hypersomnia may also be called somnolence, excessive daytime sleepiness, or prolonged drowsiness.

Signs of hypersomnia

The signs of hypersomnia caninclude:

Sleeping for 10 or more hours at a time

Excessive amounts of deep sleep

Trouble staying awake during the day.

Excessive sleepiness that isn’t reduced by taking a nap

Hypersomnia may interfere with your relationships and prevent you from enjoying activities. It can also make handling daily activities and family and work responsibilities a challenge.

Although similar, hypersomnia and fatigue are not the same. Fatigue is a feeling of exhaustion and lack of energy not relieved by sleep. However, excessive daytime sleeping and being unable to stay awake are not signs of fatigue.

Causes of hypersomnia

The following types of cancer, cancer treatment, and other medical conditions can cause hypersomnia:

Brain and central nervous system (CNS) tumors

A cancer that has spread to the brain from somewhere else in the body

Some types of chemotherapy

Other prescription and over-the-counter medications, such as the following:

Some antidepressants

Antinausea medications

Some pain medications

Sedatives, which are medications that calm or cause sleep

Antihistamines, which are medications used to treat allergy or cold symptoms

To treat hypersomnia, your doctor first needs to find and treat the cause. Treating the cause of hypersomnia helps relieve the symptoms. For example, hypersomnia related to chemotherapy usually improves after treatment ends. If other medications are causing it, your doctor may be able to substitute a different medication or adjust the dose. Your doctor may also prescribe stimulant medications to help you stay awake during the day.

The following behavioral changes may help you manage hypersomnia:

Sleep a few hours longer at night to avoid excessive sleepiness during the day.

Exercise daily in the morning or early afternoon, if possible.

Do enjoyable activities that require your full attention.

Try to go to sleep and wake up at the same time every day.

Get out of bed and stay out of bed until bedtime.

Avoid heavy meals and foods that make you sleepy during the day.

Avoid alcohol and caffeine.

Somnolence syndrome

Somnolence syndrome is a type of hypersomnia in children associated with radiation therapy to the head.

Symptoms of somnolence syndrome

The symptoms of somnolence syndrome usually occur three to 12 weeks after radiation treatment ends. It can last a few days or several weeks. The symptoms include:

Excessive drowsiness

Sleeping up to 20 hours a day

Headaches

Low-grade fever

Loss of appetite

Nausea and vomiting

Irritability

Nightmares

Nightmares are vivid, frightening dreams. They usually cause the person to wake up and remember part or most of the dream.

Most people have nightmares from time to time. However, the frequency or vividness of nightmares can increase after a cancer diagnosis and during cancer treatment. Frequent nightmares can lead to a fear of going to sleep, restless sleep, and daytime sleepiness.

Causes of nightmares

An increase in emotional stress is a common cause of nightmares. They may be a way in which the mind works through unresolved feelings and fears.

Other causes of nightmares may include:

Antibiotics

Iron supplements

Pain medications

Heart medications

Withdrawal from alcohol, pain medications, and some anti-anxiety medications

Because having cancer is frightening and stressful, it is normal to experience some nightmares during treatment and recovery. The following tips may help you cope with nightmares:

Be honest about your fears and feelings. Discuss them with a family member or friend early in the day, rather than at night.

Talk about the nightmares with a family member or friend.

Find creative ways to express the content or themes of the nightmares, such as writing about them or drawing pictures.

Make up different endings or storylines to the nightmares, and visualize them.

Remember that nightmares are not real, and they do not predict the future or cause bad things to happen. Talk with your doctor or a trained counselor if the nightmares increase or continue, cause excessive anxiety, or prevent you from sleeping well.

Cancer.Net provides timely, comprehensive, oncologist-approved information from the American Society of Clinical Oncology (ASCO), with support from the Conquer Cancer Foundation. Cancer.Net brings the expertise and resources of ASCO to people living with cancer and those who care for and about them to help patients and families make informed health care decisions.